Synthesis of the Aglycon of the Antibiotic Disciformycin
作者:Michael Wolling、Andreas Kirschning
DOI:10.1002/ejoc.201701639
日期:2018.2.7
Challenging alkenes: The synthesis of the aglycon of disciformycin, a new secondary metabolite from Pyxidicoccus fallax, with high antibacterial potency is reported. The stereocontrolled installation of the olefinic double bonds at C2–C3/C3–C4 and C12–C13, respectively, as well the orthogonal differentiation of the oxy functionalities unexpectedly were found to be key challenges of the project.
N-acyl amycolose moiety incorporated in amycolamicin, a broad-spectrum antibacterial natural product produced by soil actinomycetes, and its two anomeric methylglycosides have been synthesized enantioselectively each in 12 steps from a known methyl (R)-lactate derivative by exploiting a diastereoselective nucleophilic addition of a p-methoxybenzyloxy-substituted vinyllithium reagent to an α,β-bisalkoxy
tetrasubstituted carboncenter; and 3) an intramolecularchirality‐transferring Michael reaction of the ketoester, with neighboring‐group participation, to introduce a chiralcenter at C15 in the target molecule. In addition, we evaluated the antimalarial activity of synthetic (+)‐(15S,16R)‐16‐hydroxy‐16,22‐dihydroapparicine and its intermediate against chloroquine‐resistant Plasmodium falciparum (K1 strain)
The totalsynthesis of the antibiotic amycolamicin with a hybrid molecular architecture composed of five ring systems, which exhibits potent antibacterial activity against a wide range of drug-resistant bacteria, has been achieved in a convergent manner. A protecting-group-free intramolecular Diels–Alder reaction of a hydroxy tetraenal intermediate promoted by two equivalents of Et2AlCl, which proceeds
Comparative Ascaroside Profiling of <i>Caenorhabditis</i> Exometabolomes Reveals Species-Specific (ω) and (ω – 2)-Hydroxylation Downstream of Peroxisomal β-Oxidation
作者:Chuanfu Dong、Douglas K. Reilly、Célia Bergame、Franziska Dolke、Jagan Srinivasan、Stephan H. von Reuss
DOI:10.1021/acs.joc.8b00094
日期:2018.7.6
Molecular structures of these species-specific putative signaling molecules were elucidated by NMR spectroscopy and confirmed by total synthesis and chemical correlations. Biological activities were evaluated using attraction assays. The identification of (ω)- and (ω – 2)-hydroxyacyl ascarosides demonstrates how GC-EIMS-based ascaroside profiling facilitates the detection of novel ascaroside components